1. Field of the Invention
The present invention relates to a ray casting method using hardware.
2. Description of the Prior Art
Ray casting is known as a method of rendering using CG. In this technique, an object formed by a voxel is first arranged in a virtual three-dimensional space defined in a memory space. Internal information of the object is given as a plurality of voxel values to each voxel. A plurality of unit rays are virtually radiated from a view point present at a predetermined position in the virtual three-dimensional space. Each pixel value on a display plane is calculated based on the voxel values of the voxels present on each unit ray.
According to such a ray casting method, various internal information of the object can freely be visualized to satisfy requirements. Therefore, attention has recently been paid to the ray casting method as a new visualization technique (volume visualization) for a three-dimensional object including an organism.
However, it is necessary to calculate a path for a ray radiated from a view point and voxels on the path in real time. This is difficult to realize using hardware. Conventionally, software has mainly been used for implementation, and a lot of processing time is required. In a case where the view point and the object are moved in the virtual three-dimensional space, it is difficult to generate images reflecting their movement in real time.